Long Term Ammunition Storage Made Easy

It seems more and more people are wanting to store ammunition for longer periods of time. The concern with the long term storage of ammunition storage is the corrosion on the shell casings. Corrosion comes from excessive moisture reacting with the brass casing or the primer making the round dangerous to fire. Nevertheless there are very easy ways to store your ammunition for a considerable amount of time and if you have a ammunition stock pile you are wanting to store there are a few things you need to think about. The key to successful storage is to remember: humidity is the enemy! You can easily store modern ammunition in paper boxes for several years inside your house, which typically has a controlled humidity level, without issue. I have even seen brass cased ammunition stored in cardboard boxes in a horse barn for one to two years (not that I would recommend it) without any noticeable corrosion on the casings. This does not address the challenges of storing ammunition for 3-5 years or longer.

It is important to note not to store you ammunition longer than necessary. Now, what do we mean by this? Rotate your ammunition whenever possible. So, instead of storing 5000 rounds of 5.56 or .223 for 10 years, mark each ammo can with the date you acquired the ammunition and the ammunition type. As you acquire more ammunition, of equivalent type, use the oldest ammunition first. This provides you a method of keeping your ammunition stock as fresh as possible. Of course, there is more to ammunition than caliber. You will need to mark your ammo cans with all the appropriate information. Most shooters are not going to open a case of 62 grain M885 green tip for target practice and store cheap 55 grain Wolf 5.56 ammunition. They both might be 5.56 ammunition, but they are very different in terms of performance.

Next, keep the humidity out! If you are storing ammunition in a less than ideal location, humidity will likely be your biggest enemy. The DoD stores ammunition in non-environmentally controlled warehouses for decades. If you have good ammo cans and pack your ammo well you can easily have your ammunition survive very long term storage. During Desert Storm (that was 1990-1991) Soldiers were issued 5.56 ammunition that was manufactured at Lake City (LC 67) (manufactured in 1967) that performed well showed no signs of degradation. You can easily store your own ammunition by ensuring the humidity inside the ammo can is low. The key to success is to lower the humidity in all the packing material before sealing the your ammunition in an airtight container such as an ammo can. If you are storing loose ammunition this is not really an issue since there is nothing to trap humidity, but air. If you are storing your ammunition in cardboard boxes inside the ammo can you will need to get the humidity out of the cardboard before sealing the can for storage. The easiest way is to use a dehumidifier, you probably have on inside your gun safe to protect your guns. Placing the ammo and container (unsealed and open) inside the safe several days will draw the moisture out of all the packing material to ensure you start with the proper humidity conditions. Next take a few new desiccant packets (1/2 or 1 oz packets) and place them in the ammo can. Finally, a worthy addition to the storage container is a humidity sensor card to provide a quick visual inspection as you spot check your ammo. All you need to do now is seal the ammo can and it should give you years of successful storage.

Now that you have your ammunition sealed and stored you will need to spot check it every 12 to 24 months. The key point to remember is typically winter provides lower ambient humidity and summer is a much higher humidity, at least here on the East Coast, so adjust your checks to correspond with a low a humidity season for your area. This will decrease the impact the your check will have on your interior humidity. If you placed the humidity sensor card in the ammo can, your checks will only take a few second. Simply, inspect the card to ensure the humidity is under about 30%, remove the existing desiccant packets and replace with new desiccant packets. The cost of desiccant packets for a can of ammunition should be less than $1 and the humidity sensor card can be found for less than $.50. This is really a trivial amount to protect the typically hundreds of dollars of ammunition that is stored in one ammo can.

Lee retired from the U.S Army in 2008 as a First Sergeant where he saw combat action during both Desert Storm and Iraqi Freedom. He led a physical security detachment in Central America; subsequently, ran a law and order detachment in Europe. Post 9/11 he was detailed with installation physical security which included both military and DA police training and operations, local and state law enforcement liaison.

Is it ok to store ammo in a sealed container, say pvc pipe capped off of course at both ends with some desiccant packets, under ground, below the frost line for a extended amount of time? I know this sounds weird to ask im not a gun nut or am i waiting for the apocalypse, im just on a tight budget and have lack of space, with a small child in the house safety is number one to me. I only have a small lock box for my weapon (dont have the money or space for a lager 1). I was told that this would be fine to do. With the rising cost of ammo id rather buy it now in a larger amount and store it. Any advice would be appreciated, thank you.

Rob: Whether the storage location is above or below ground is not nearly as relevant as the humidity level inside your container. The humidity is what allows the damage to happen, so if you properly seal a container then the humidity should not change. PVC is a much better choice for direct burial than metal.

@Matt: that is an interesting question, some food quality bags are designed to breath. So, yes, moisture can move into the bag. The bags designed to remove air (with a little pump) remain air tight. I will stand by my need for dessicant even in this situation as the residual air will have a level of moisture that will eventually condense on your ammunition. The issue is not “new” moisture, but the residual humidity in the container when it is sealed. Now, with that said, remember food quality bags are designed for short versus longterm storage, so there is no telling how long the seal will actually last. Once the seal is compromised you begin to let moisure back in to the enviroment.

I have some tracer ammunition and am wondering if this is any different to store than normal ammo? I’m just trying to be safe because i’m not sure of the different chemicals, should I just store it as I do my other ammo, by keeping the moisture out? Thanks.

@Kyle, We don’t believe there is any significant difference in storage of tracer and ball ammunition. The military stores ball, tracer and armor piercing (AP) together, so the storage is identical. most of the M-60 ammunition I was issues during Desert Storm was LC 68. There were other other lots all the training ammunition in the States was Vietnam era vintage, so storage of tracers should be just as simple, as long as you get the humidity to a safe level.

I keep my extra ammo in ammo cans with the desicant packs inside my garage in a cabinet. My problem is with the heat here along the colorado river it is real dry and hot up to 110 degrees in my garage, will the heat have adverse effects on my ammo over long term.

I have a question about storage, but not so much about humidity but temperature. I live in Arizona, which is why the humidity issue isn’t as big a deal as is temperature. Due to space, I’ve had to put my safe in the garage. In summer temperatures can get over 110 degrees (inside a garage is probably higher) for months. In the winter, temperatures can drop to freezing or lower. I have an Eva-dry dehumidifier hanging in the safe, which in the 6 months it’s been in the safe, hasn’t changed color, meaning it hasn’t needed to be plugged in to dry. Will the extreme high temperature degrade the gun powder? Thanks!

Humidity should always be considered a potential threat no matter what State you live in – condensation should be considered by those living even in AZ, CA, TX, etc. Dessicant packets can be found on “auction” sites (eg – eBay) rather inexpensively and in bulk; also oxygen absorbers.

Just curious if CO2 has any detrimental affect on ammo. I have stored lots of ammo in ammo cans with CO2 to replace the air. ( it’s heavier than air and will remain in an ammo can ) Dessicant pacs included in the can should keep them dry for years! Your opinion please!

Dave, I can’t say for certain, but inert gases are non reactive to chemical processes, like oxidation, I don’t know if CO2 is going to provide the same results. The dessicant will remove residual moisture remaining in the container. Maybe we have a chemist out there that cares to chime in….

I might be able to shed some light on the chemistry, and put my education to some sort of use. CO2 can make water acidic, It forms carbonic acid in water. So if there was moisture in the container, it could be acidified by the CO2. Not that it would be very corrosive. A better gas to purge the container with would be argon. Argon is inert and will not react with anything.

[...] Here are 3 refs for long term storage- All use these 3 basic principles 1)Keep it dry 2)rotation 3)date stamp the box(es) LONG TERM AMMUNITION STORAGE Long term ammo storage Long Term Ammunition Storage Made Easy | Aggressive Defensive Solutions [...]

Great article! I store mine in theor boxes but in the MTM plastic ammo cans. I use the silica packs, but love the idea of the humidity cards. Will pick some up. All my stufff is in a finished room in my basement. An electric baseboard kills the humiidity in the winter…and now I am moving over to a dehumidifier as the warmer weather comes in. I also have a few digitla readers in different parts of the room.

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